Editing Alternating current (section)

== History ==
The first [[alternator]] to produce alternating current was an electric generator based on [[Michael Faraday]]'s principles constructed by the French instrument maker [[Hippolyte Pixii]] in 1832.<ref>{{Cite web |url=http://www.magnet.fsu.edu/education/tutorials/java/pixiimachine/index.html |title=Pixii Machine invented by Hippolyte Pixii, National High Magnetic Field Laboratory |access-date=2012-03-23 |archive-url=https://web.archive.org/web/20080907092008/http://www.magnet.fsu.edu/education/tutorials/java/pixiimachine/index.html |archive-date=2008-09-07 |url-status=dead}}</ref> Pixii later added a [[Commutator (electric)|commutator]] to his device to produce the (then) more commonly used direct current. The earliest recorded practical application of alternating current is by [[Guillaume Duchenne]], inventor and developer of [[electrotherapy]]. In 1855, he announced that AC was superior to [[direct current]] for electrotherapeutic triggering of muscle contractions.<ref>{{cite book|isbn=9780853240631|last=Licht|first=Sidney Herman|chapter=History of Electrotherapy|title=Therapeutic Electricity and Ultraviolet Radiation|edition=2|location=New Haven|year=1967|pages=1–70}}</ref> Alternating current technology was developed further by the Hungarian [[Ganz Works]] company in the 1870s, and, in the 1880s, by [[Sebastian Ziani de Ferranti]], [[Lucien Gaulard]], and [[Galileo Ferraris]].

In 1876, Russian engineer [[Pavel Yablochkov]] invented a lighting system where sets of induction coils were installed along a high-voltage AC line. Instead of changing voltage, the primary windings transferred power to the secondary windings which were connected to one or several [[electric candle]]s (arc lamps) of his own design,<ref name="maglab" /><ref>{{cite journal |url=https://books.google.com/books?id=ksa-S7C8dT8C&pg=RA2-PA283 |page=283 |journal=[[Nature (journal)|Nature]] |issue=534 |volume=21 |title=Gas and Electricity in Paris |date=Jan 22, 1880 |last=De Fonveille |first=W. |access-date=Jan 9, 2009 |bibcode=1880Natur..21..282D |doi=10.1038/021282b0 |doi-access=free}}</ref> used to keep the failure of one lamp from disabling the entire circuit.<ref name="maglab" /> In 1878, the [[Ganz Works|Ganz factory]], Budapest, Hungary, began manufacturing equipment for electric lighting and, by 1883, had installed over fifty systems in [[Austria-Hungary]]. Their AC systems used arc and incandescent lamps, generators, and other equipment.<ref>{{Cite book | url = https://books.google.com/books?id=g07Q9M4agp4C&q=Networks+of+Power:+Electrification+in+Western+Society,+1880-1930+ganz&pg=PA96 | last = Hughes | first = Thomas P. | title = Networks of Power: Electrification in Western Society, 1880–1930 | publisher = The Johns Hopkins University Press | location = Baltimore | year= 1993 | page = 96 | access-date = Sep 9, 2009 | isbn = 0-8018-2873-2}}</ref>

=== Transformers ===
The development of the alternating current [[transformer]] to change voltage from low to high level and back, allowed generation and consumption at low voltages and transmission, over great distances, at high voltage, with savings in the cost of conductors and energy losses. A bipolar open-core [[Transformer|power transformer]] developed by [[Lucien Gaulard]] and [[John Dixon Gibbs]] was demonstrated in London in 1881, and attracted the interest of [[Westinghouse Electric (1886)|Westinghouse]]. They exhibited an AC system powering arc and incandescent lights was installed along five railway stations for the Metropolitan Railway in [[London]] and a single-phase multiple-user AC distribution system [[Turin]] in 1884.<ref>{{Cite journal |last=Allerhand |first=Adam |date=2019 |title=Early AC Power: The First Long-Distance Lines [History] |url=https://ieeexplore.ieee.org/document/8802330 |journal=IEEE Power and Energy Magazine |volume=17 |issue=5 |pages=82–90 |doi=10.1109/MPE.2019.2921059 |issn=1540-7977|url-access=subscription }}</ref> These early induction coils with open magnetic circuits were inefficient at transferring power to [[Electrical load|loads]].{{fact|date=December 2024}} Until about 1880, the paradigm for AC power transmission from a high voltage supply to a low voltage load was a series circuit.{{fact|date=December 2024}} Open-core transformers with a ratio near 1:1 were connected with their primaries in series to allow use of a high voltage for transmission while presenting a low voltage to the lamps.{{fact|date=December 2024}} The inherent flaw in this method was that turning off a single lamp (or other electric device) affected the voltage supplied to all others on the same circuit.{{fact|date=December 2024}} Many adjustable transformer designs were introduced to compensate for this problematic characteristic of the series circuit, including those employing methods of adjusting the core or bypassing the magnetic flux around part of a coil.<ref name="FJU1889" /> The direct current systems did not have these drawbacks, giving it significant advantages over early AC systems.

In the UK, [[Sebastian Ziani de Ferranti|Sebastian de Ferranti]], who had been developing AC generators and transformers in London since 1882, redesigned the AC system at the [[Grosvenor Gallery#Generating station|Grosvenor Gallery power station]] in 1886 for the London Electric Supply Corporation (LESCo) including alternators of his own design and open core transformer designs with serial connections for utilization loads - similar to Gaulard and Gibbs.{{sfnp|Hughes|1993|p=98}} In 1890, he designed [[Deptford Power Station|their power station at Deptford]]<ref>{{cite web|url=http://www.mosi.org.uk/collections/explore-the-collections/ferranti-online/timeline.aspx|title=Ferranti Timeline|archive-url=https://web.archive.org/web/20151003002335/http://www.mosi.org.uk/collections/explore-the-collections/ferranti-online/timeline.aspx|archive-date=2015-10-03| website=Museum of Science and Industry (Manchester)|access-date=February 22, 2012}}</ref> and converted the Grosvenor Gallery station across the Thames into an [[electrical substation]], showing the way to integrate older plants into a universal AC supply system.{{sfnp|Hughes|1993|p=208}}

[[File:ZBD team.jpg|thumb|right|The Hungarian ZBD Team ([[Károly Zipernowsky]], [[Ottó Bláthy]], [[Miksa Déri]]), inventors of the first high efficiency, closed-core shunt connection [[transformer]]]]

[[File:DBZ trafo.jpg|right|thumb|The prototype of the ZBD transformer on display at the Széchenyi István Memorial Exhibition, [[Nagycenk]] in [[Hungary]]]]

In the autumn{{Ambiguous|date=January 2023}} of 1884, [[Károly Zipernowsky]], [[Ottó Bláthy]] and [[Miksa Déri]] (ZBD), three engineers associated with the [[Ganz Works]] of Budapest, determined that open-core devices were impractical, as they were incapable of reliably regulating voltage.{{sfnp|Hughes|1993|p=95}} Bláthy had suggested the use of closed cores, Zipernowsky had suggested the use of [[Shunt (electrical)|parallel shunt connections]], and Déri had performed the experiments;<ref>{{cite book|url=https://archive.org/details/creatingtwentiet0000smil|url-access=registration|quote=ZBD transformer.|last=Smil|first=Vaclav|title=Creating the Twentieth Century: Technical Innovations of 1867–1914 and Their Lasting Impact|location=Oxford |publisher=Oxford University Press|year=2005|page=[https://archive.org/details/creatingtwentiet0000smil/page/71 71]|isbn=978-0-19-803774-3}}</ref> In their joint 1885 patent applications for novel transformers (later called ZBD transformers), they described two designs with closed magnetic circuits where copper windings were either wound around a ring core of iron wires or else surrounded by a core of iron wires.<ref name="FJU1889" /> In both designs, the magnetic flux linking the primary and secondary windings traveled almost entirely within the confines of the iron core, with no intentional path through air (see [[transformer#Toroidal cores|toroidal cores]]). The new transformers were 3.4 times more efficient than the open-core bipolar devices of Gaulard and Gibbs.<ref>{{cite web |last=Jeszenszky|first=Sándor |title=Electrostatics and Electrodynamics at Pest University in the Mid-19th Century |url=http://ppp.unipv.it/Collana/Pages/Libri/Saggi/Volta%20and%20the%20History%20of%20Electricity/V%26H%20Sect2/V%26H%20175-182.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://ppp.unipv.it/Collana/Pages/Libri/Saggi/Volta%20and%20the%20History%20of%20Electricity/V%26H%20Sect2/V%26H%20175-182.pdf |archive-date=2022-10-09 |url-status=live |publisher=[[University of Pavia]]|access-date=Mar 3, 2012}}</ref> The Ganz factory in 1884 shipped the world's first five high-efficiency AC transformers.<ref name="Halacsy (1961)" /> This first unit had been manufactured to the following specifications: 1,400 W, 40&nbsp;Hz, 120:72 V, 11.6:19.4 A, ratio 1.67:1, one-phase, shell form.<ref name="Halacsy (1961)" />

The ZBD patents included two other major interrelated innovations: one concerning the use of parallel connected, instead of series connected, utilization loads, the other concerning the ability to have high turns ratio transformers such that the supply network voltage could be much higher (initially 140 to 2000&nbsp;V) than the voltage of utilization loads (100&nbsp;V initially preferred).<ref>{{cite web |title=Hungarian Inventors and Their Inventions |url=http://www.institutoideal.org/conteudo_eng.php?&sys=biblioteca_eng&arquivo=1&artigo=94&ano=2008 |publisher=Institute for Developing Alternative Energy in Latin America |access-date=Mar 3, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120322223457/http://www.institutoideal.org/conteudo_eng.php?&sys=biblioteca_eng&arquivo=1&artigo=94&ano=2008 |archive-date=2012-03-22}}</ref><ref>{{cite web |title=Bláthy, Ottó Titusz|url=http://www.omikk.bme.hu/archivum/angol/htm/blathy_o.htm|publisher=Budapest University of Technology and Economics, National Technical Information Centre and Library |access-date=Feb 29, 2012}}</ref> When employed in parallel connected electric distribution systems, closed-core transformers finally made it technically and economically feasible to provide electric power for lighting in homes, businesses and public spaces.<ref>{{cite web |title=Bláthy, Ottó Titusz (1860–1939) |url=http://www.hpo.hu/English/feltalalok/blathy.html |publisher=Hungarian Patent Office |access-date=Jan 29, 2004 |archive-date=December 2, 2010 |archive-url=https://web.archive.org/web/20101202031830/http://www.hpo.hu/English/feltalalok/blathy.html |url-status=dead}}</ref><ref>{{cite web |last=Zipernowsky|first=K.|author2= Déri, M.|author3= Bláthy, O.T. | url=http://www.freepatentsonline.com/0352105.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.freepatentsonline.com/0352105.pdf |archive-date=2022-10-09 |url-status=live|title=Induction Coil|publisher=U.S. Patent 352 105, issued Nov. 2, 1886|access-date=July 8, 2009}}</ref>
 
The other essential milestone was the introduction of 'voltage source, voltage intensive' (VSVI) systems'<ref>American Society for Engineering Education. Conference – 1995: Annual Conference Proceedings, Volume 2, (PAGE: 1848)</ref> by the invention of constant voltage generators in 1885.{{sfnp|Hughes|1993|p=96}} In early 1885, the three engineers also eliminated the problem of [[eddy current]] losses with the invention of the lamination of electromagnetic cores.<ref>{{cite book|author=Electrical Society of Cornell University|title=Proceedings of the Electrical Society of Cornell University|publisher=Andrus & Church|year=1896|page=39}}</ref> Ottó Bláthy also invented the first AC [[electricity meter]].<ref>{{cite web |author=Eugenii Katz |url=http://people.clarkson.edu/~ekatz/scientists/blathy.html |title=Blathy |publisher=People.clarkson.edu |access-date=2009-08-04| archive-url = https://web.archive.org/web/20080625015707/http://people.clarkson.edu/~ekatz/scientists/blathy.html| archive-date = June 25, 2008}}</ref><ref>{{cite journal |last=Ricks |first=G.W.D. |title=Electricity Supply Meters |journal=Journal of the Institution of Electrical Engineers |date=March 1896 |volume=25 |number=120 |pages=57–77 |doi=10.1049/jiee-1.1896.0005 |url=https://archive.org/stream/journal06sectgoog#page/n77/mode/1up}} Student paper read on January 24, 1896, at the Students' Meeting.</ref><ref>''The Electrician'', Volume 50. 1923</ref><ref>Official gazette of the United States Patent Office: Volume 50. (1890)</ref>

===Adoption===

The AC power system was developed and adopted rapidly after 1886. In March of that year, Westinghouse engineer [[William Stanley, Jr.|William Stanley]], designing a system based on the Gaulard and Gibbs transformer,<ref>{{cite book|last=Skrabec|first=Quentin R.|title=George Westinghouse: Gentle Genius|publisher=Algora Publishing|year=2007|page=102|isbn=978-0-87586-508-9|url=https://books.google.com/books?id=C3GYdiFM41oC&pg=PA102}}</ref> demonstrated a lighting system in [[Great Barrington, Massachusetts|Great Barrington]]:  A [[Siemens]] generator's voltage of 500 volts was converted into 3000 volts, and then the voltage was stepped down to 500 volts by six Westinghouse transformers. With this setup, the Westinghouse company successfully powered thirty 100-volt incandescent bulbs in twenty shops along the main street of Great Barrington.<ref>{{cite journal |last1=Brusso |first1=Barry|last2=Allerhand |first2=Adam |date=January 2021 |title=A Contrarian History of Early Electric Power Distribution|volume= |issue= |doi= 10.1109/MIAS.2020.3028630|url=https://ieeexplore.ieee.org/document/9292399 |journal=IEEE Industry Applications Magazine |page=13 |publisher=IEEE.org |s2cid=230605234 |access-date=January 1, 2023|archive-date=December 12, 2020 |archive-url=https://web.archive.org/web/20201212083429/https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=9292399 |doi-access=free}}</ref><ref>{{cite book|author=Clark W. Gellings|title=The Smart Grid Enabling Energy Efficiency and Demand Response|publisher=[[River Publishers]]|year=2020|page=62|isbn=9781000355314|url=https://books.google.com/books?id=0xkOEAAAQBAJ&dq=siemens+generator+%22great+barrington%22&pg=PT62}}</ref> By the fall of that year Ganz engineers installed a ZBD transformer power system with AC generators in [[Rome]].<ref name="IEC Techline" />

[[File:WestinghouseEarlyACSystem1887-USP373035.png|thumb|Westinghouse Early AC System 1887<br /> ([https://web.archive.org/web/20090325121254/http://www.pat2pdf.org/patents/pat373035.pdf US patent 373035])]]

Based on Stanley's success, the new [[Westinghouse Electric Corporation|Westinghouse Electric]]<ref>{{cite book|title=History of Tinicum Township (PA) 1643–1993|publisher=Tinicum Township Historical Society|year=1993|url=http://tthsdelco.org/wp-content/uploads/2014/02/History%20of%20Tinicum%20Twp.pdf|archive-url=https://web.archive.org/web/20150423202458/http://tthsdelco.org/wp-content/uploads/2014/02/History%20of%20Tinicum%20Twp.pdf|archive-date=April 23, 2015|url-status=live}}</ref> went on to develop alternating current (AC) electric infrastructure throughout the United States. The spread of Westinghouse and other AC systems triggered a push back in late 1887 by [[Thomas Edison]] (a proponent of direct current), who attempted to discredit alternating current as too dangerous in a public campaign called the "[[war of the currents]]". 

In 1888, alternating current systems gained further viability with the introduction of a functional [[AC motor]], something these systems had lacked up till then. The design, an [[induction motor]], was independently invented by [[Galileo Ferraris]] and [[Nikola Tesla]] (with Tesla's design being licensed by Westinghouse in the US). This design was independently further developed into the modern practical [[three-phase]] form by [[Mikhail Dolivo-Dobrovolsky]] and [[Charles Eugene Lancelot Brown]] in Germany on one side,<ref>{{cite book|first1=Arnold|last1=Heertje|first2=Mark|last2=Perlman|title=Evolving Technology and Market Structure: Studies in Schumpeterian Economics|year=1990 |isbn=9780472101924|page=138|publisher=University of Michigan Press}}</ref> and [[Jonas Wenström]] in Sweden on the other, though Brown favored the two-phase system.

The [[Ames Hydroelectric Generating Plant]], constructed in 1890, was among the first hydroelectric alternating current power plants. A long-distance transmission of single-phase electricity from a hydroelectric generating plant in Oregon at Willamette Falls sent power fourteen miles downriver to downtown Portland for street lighting in 1890.<ref>{{Cite journal |date=1915|title=Electric Transmission of Power |journal=General Electric Review |volume=XVIII}}</ref>  In 1891, another transmission system was installed in Telluride Colorado.<ref>{{Cite journal |date=1915|title=Electric Transmission of Power|journal=General Electric|volume=XVIII}}</ref> The first [[Three-phase electric power|three-phase system]] was established in 1891 in [[Frankfurt]], Germany. The [[Tivoli, Lazio|Tivoli]]–[[Rome]] transmission was completed in 1892.<ref name="Holjevac" /> The San Antonio Canyon Generator was the third commercial single-phase hydroelectric AC power plant in the United States to provide long-distance electricity.  It was completed on December 31, 1892, by [[Almarian Decker|Almarian William Decker]] to provide power to the city of [[Pomona, California]], which was 14 miles away. Meanwhile, the possibility of transferring electrical power from a waterfall at a distance was explored at the [[Grängesberg]] mine in Sweden. A {{val|45|ul=m}} fall at Hällsjön, Smedjebackens kommun, where a small iron work had been located, was selected. In 1893,  a three-phase {{val|9.5|ul=Kilovolt{{!}}kv}} system was used to transfer 400 [[horsepower]] a distance of {{val|15|ul=km}}, becoming the first commercial application.<ref>{{cite book | last= Hjulström | first= Filip | title= Elektrifieringens utveckling i Sverige, en ekonomisk-geografisk översikt | year= 1940 | url= https://www.antikvariat.net/sv/rod151504-elektrifieringens-utveckling-i-sverige-en-ekonomisk-geografisk-oversikt-hjulstrom-filip | trans-quote= Excerpt taken from YMER 1941, häfte 2.Utgiven av Sällskapet för antropologi och geografi: Meddelande från Upsala univeristets geografiska institution, N:o 29, published by Esselte ab, Stockholm 1941 no. 135205}}</ref> In 1893, Westinghouse built an alternating current system for the [[Chicago World Exposition]].<ref name="Holjevac" /> In 1893, Decker designed the first American commercial [[three-phase]] power plant using alternating current—the hydroelectric [[Mill Creek No. 1 Hydroelectric Plant]] near [[Redlands, California]].  Decker's design incorporated 10&nbsp;kV three-phase transmission and established the standards for the complete system of generation, transmission and motors used in USA today. The original Niagara Falls [[Adams Power Plant]]  with three two-phase generators was put into operation in August 1895, but was connected to the remote transmission system only in 1896. The [[Jaruga Hydroelectric Power Plant]] in Croatia was set in operation two days later, on 28 August 1895. Its [[electric generator|generator]] (42&nbsp;Hz, 240&nbsp;kW) was made and installed by the Hungarian company [[Ganz]], while the transmission line from the power plant to the City of [[Šibenik]] was {{convert|11.5|km|sp=us}} long, and the municipal distribution grid 3000&nbsp;V/110&nbsp;V included six transforming stations.<ref name="Holjevac" />

Alternating current circuit theory developed rapidly in the latter part of the 19th and early 20th century. Notable contributors to the theoretical basis of alternating current calculations include [[Charles Steinmetz]], [[Oliver Heaviside]], and many others.<ref>{{Cite book|url=https://books.google.com/books?id=f5FqsDPVQ2MC&q=theoretical++alternating+current++Oliver+Heaviside&pg=PA1229|title=Companion Encyclopedia of the History and Philosophy of the Mathematical Sciences|first=I.|last=Grattan-Guinness|date=September 19, 2003|publisher=JHU Press|via=Google Books|isbn=978-0-8018-7397-3}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=lew5IC5piCwC&q=theoretical++alternating+current++Charles+Steinmetz&pg=PA329|title=Mathematics in Historical Context|first=Jeff|last=Suzuki|date=August 27, 2009|publisher=MAA|via=Google Books|isbn=978-0-88385-570-6}}</ref> Calculations in unbalanced three-phase systems were simplified by the [[symmetrical components]] methods discussed by [[Charles LeGeyt Fortescue]] in 1918. <!-- discuss network analyzer and digital computer network analysis -->